The present invention relates to magnetic recording media, such as magnetic disks, which can contribute to the provision of a magnetic disk unit having excellent slide-resistance reliability, to the substrate for constituting such magnetic recording media, and to a method of producing the magnetic recording media.
In the field of recent magnetic recording media, high-density recording of information has been advanced in connection with the small-size and large-capacity of magnetic disk units. In order to achieve high-density recording, it is important to reduce the distance between the magnetic recording medium and the head. When the magnetic recording medium and the head have smooth surfaces, the place where both are made in contact at the time of contact start/stop (CSS) has high stiction property. Thus, there is some possibility that an accident due to the stickiness occurs under the presence of a lubricant. Therefore, it was proposed that the region (CSS zone) in which the head contacts with the magnetic medium at the time of CSS is required to have low stickiness, and that the CSS zone should have higher bumps scattered than the region (data zone) in which information is stored on the medium in order for the floating margin to the head to be as wide as possible within the data zone. For example, as disclosed in JP-A-3-272018, the entire surface of the substrate of the magnetic recording medium is mechanically processed to have bumps of a roughness (Rp) less than 2.54 nm, and then only the CSS zone is processed by laser to have ring-shaped bumps. Also, in JP-A-8-147662, a metal capable of forming carbide is sputtered on the entire surface of a carbon substrate to form highly close bumps.
JP-A-8-180401 and JP-A-9-259418 disclose a background of the present invention.